Genetic characterization and phylogenetic analysis of porcine circovirus type 2 strains present in Cuban swine herds

Porcine circovirus type 2 (PCV2) is the essential infectious agent of postweaning multisystemic wasting syndrome (PMWS) considered as one of the most important swine diseases worldwide. One of the main risk factors reported for the development of PMWS is the PCV2 genotype. The presence of PCV2 in Cuban swine herds has been reported recently. However, genetic information about these viruses is not available yet. Hence, the objectives of this study were to classify the Cuban porcine circovirus type 2 sequences as well as to investigate the genetic diversity and the putative origins of the virus circulating in Cuban swine herds. PCV2 Cuban sequences appeared to be close related when an analysis of the entire viral genome sequences was performed. The main variations on amino acid sequences of the capsid protein were found within the immunoreactive areas. All the Cuban PCV2 sequences analyzed belonged to genotype 1 and were located within the same Cluster (1A). Interestingly, five of them were clustered with high confident values with those described as the PCV2 variants associated with severe porcine circovirus diseases reported in Canada from the late 2004 to 2006. Pigs imported from this source appeared to be the most probable origin of the viruses circulating in Cuban swine herds currently. The fact that one sequence was not clustered with any other group of PCV2 within genotype 1 might suggest that different introductions of the agent in the country from unknown sources have occurred.